It turns out, that tattoo ink can travel throughout your body and settle in lymph nodes.

Members from the European Synchrotron Radiation Facility in France, and the German Federal Institute for Risk Assessment, Physikalisch-Technische Bundesanstalt, and Ludwig-Maximilians University, used synchrotron X-ray fluorescence in four human cadavers with tattoos and 1 without in the slightly macabre experiment to know exactly where the ink travels to.

As the authors explain in the study, it would have been unethical to test this on live animals since those creatures would not be able to give permission to be tattooed.

Because of the prevalence of tattoos these days, the researchers wanted to find out if the ink could be harmful in some way.

"The increasing prevalence of tattoos provoked safety concerns with respect to particle distribution and effects inside the human body."

It works like this: Since lymph nodes filter lymph, which is the fluid that carries white blood cells throughout the body in an effort to fight infections that are encountered, that is where some of the ink particles collect.

Titanium dioxide appears to be the thing that travels. It’s a white tattoo ink pigment that’s mixed with other colors all the time to control shades.

The study’s authors will keep working on this in the meantime.

“In future experiments we will also look into the pigment and heavy metal burden of other, more distant internal organs and tissues in order to track any possible bio-distribution of tattoo ink ingredients throughout the body. The outcome of these investigations not only will be helpful in the assessment of the health risks associated with tattooing but also in the judgment of other exposures such as, e.g., the entrance of TiO2 nanoparticles present in cosmetics at the site of damaged skin.”

Even the optimists among us would have to admit 2018 was a challenging year. The fractured world that became the focus of our 2018 Annual Meeting a year ago came under further pressure from populist rhetoric and rising nationalist agendas. At the same time, the urgent need for coordinated global action in areas such as climate change, inequality and the impact of automation on jobs became more intense.